Histological and histochemical study of the proventriculus ( Ventriculus glandularis ) of common starling ( Sturnus vulgaris )

'Plasticosis': Characterising macro- and microplastic-associated fibrosis in seabird tissues

As biota are increasingly exposed to plastic pollution, there is a need to closely examine the sub-lethal 'hidden' impacts of plastic ingestion. This emerging field of study has been limited to model species in controlled laboratory settings, with little data available for wild, free-living organisms. Highly impacted by plastic ingestion, Flesh-footed Shearwaters (Ardenna carneipes) are thus an apt species to examine these impacts in an environmentally relevant manner. A Masson's Trichrome stain was used to document any evidence of plastic-induced fibrosis, using collagen as a marker for scar tissue formation in the proventriculus (stomach) of 30 Flesh-footed Shearwater fledglings from Lord Howe Island, Australia. Plastic presence was highly associated with widespread scar tissue formation and extensive changes to, and even loss of, tissue structure within the mucosa and submucosa. Additionally, despite naturally occurring indigestible items, such as pumice, also being found in the gastrointestinal tract, this did not cause similar scarring. This highlights the unique pathological properties of plastics and raises concerns for other species impacted by plastic ingestion. Further, the extent and severity of fibrosis documented in this study gives support for a novel, plastic-induced fibrotic disease, which we define as 'Plasticosis,'.

Anatomical distribution of celiac artery with histochemical investigation to the proventriculus of barn owl (Tyto alba)

The present investigation was performed to transpire the celiac artery distribution, histological, and histochemical characteristics of the proventriculus in eight adult barn owls (Tyto alba) of both sexes. Six birds were subjected to anatomical investigation of the celiac artery distribution and two owls were used for routine histomorphological techniques. The proventricular length, width, and lumen diameter were measured at 14.18 ± 0.08, 6.46 ± 0.17 and 1.46 ± 0.14 mm, respectively. The celiac artery in barn owl gave off six collateral arteries before its division into right and left branches. The arteria hepatica dextra does not originate from the right celiac division. Unlike other birds, there were left dorsal and left ventral gastric arteries. Histologically, the proventricular wall consisted of main four tunics. The lining epithelium is simple columnar with plicae and sulci. The muscularis mucosa is absent. The submucosal gastric glands were in two rows in the cranial proventricular portion while were arranged in one parallel row in the middle and caudal portions with pear-shaped, oval to round tubuloalveolar lobules. The mucosal folds, tubular mucosal glands, tubuloalveolar lobules, and their mucus secretion in the collecting ducts were positively reacted to PAS and alcian blue stains. The interlobular collagen fibers, elastic fibers, and reticular network were intensely reacted to Masson’s trichrome, Orcein, and Gomori's reticulin stains, respectively. These anatomical and histomorphological features of the barn owl proventriculus were aimed to provide recent data comparable with most species of birds and the presence of diversity that might be attributed to their feeding demeanor.

Anatomical, histochemical, and immunohistochemical observations on the gastrointestinal tract of Gallinula chloropus (Aves: Rallidae)

Background

Gallinula chloropus (Linnaeus, 1758) is a wild aquatic omnivorous bird characterized by a marked resistance to harsh environmental conditions and a worldwide distribution. In this study, anatomical, morphometrical, histochemical, and immunohistochemical techniques were employed to study the structure of the gastrointestinal tract of Gallinula chloropus.

Results

The esophagus appeared tubular with no distinct crop. Both superficial (SPG) and deep (DPG) proventricular glands were present. The DPG filled about two-thirds of the total wall thickness. Histochemically, the mucosubstances revealed mixed alcian blue-PAS positive reactions. They were mainly localized in the acini of the esophageal glands and SPG, gastric surface epithelium, duct system of DPG, and intestinal goblet cells. The highest number of goblet cells per every 1 mm2 of the intestinal mucosa was seen within the ileum and rectum, 2555 ± 468 and 2607 ± 653 respectively. Notably, glucagon immunoreactive (IR) cells were abundant in the mucosa of the small and large intestines and the proventriculus, while somatostatin IR cells were concentrated within the acini of the DPG. IR cells for the mitosis marker phospho-histone H3 (PHH3) were highest within the entire intestinal crypts and mucosa-associated lymphoid tissues (MALT). In contrast, cells IR for the apoptosis marker C.CASP3 were remarkable in epithelial cells at the tips of intestinal villi and in MALT, reflecting the dynamic nature of the latter mentioned structures.

Conclusions

The findings of the present study advance our knowledge of the gross and microscopic anatomy of the gastrointestinal tract in wild birds and could help to enhance the productivity of Aves via improving gut health.

Histomorphological, histochemical and scanning electron microscopic investigation of the proventriculus (Ventriculus glandularis) of the hooded crow (Corvus cornix)

The current investigation aimed to clarify the histomorphological features, scanning electron microscopy (SEM) and histochemistry of the proventriculus in the adult hooded crow (Corvus cornix). Twenty-two adult birds of both sexes were collected from El-Fayoum and Beni-Suef governorates, Egypt; ten were used for anatomical investigation, two were scanned using SEM, and ten were subjected to routine histological technique. The obtained anatomical results revealed a small-sized spindle-shaped proventriculus obliquely located in the left ventral part of the body cavity with an average body weight, length and diameter of 1.689 ± 0.231 gm, 1.54 ± 0.383cm and 3.51 ± 0.416cm, respectively. The histological examination revealed a typical tubular organ. The mucosa exhibited several plicae and sulci that were lined with simple columnar cells. The lamina propria was composed of collagenous connective tissue infiltrated by lymphocytes, lymphatic aggregations and tubular glands. The submucosa consisted of collagenic fibres and compound tubuloalveolar glandular lobules lined with oxynticopeptic cells and enteroendocrine cells. The oxynticopeptic cells reacted negatively with PAS and Alcian Blue stains, whereas the ductal cells reacted positively with PAS only. Enteroendocrine cells were seen singly in the lamina epithelialis mucosae and were abundant in submucosal glands. The tunica musclaris was arranged in two layers covered by serosa. The proventricular glands' openings were noticed by SEM as raised tubes with regular circular outlines surrounded by anastomosed microscopic folds. The obtained histomorphological structure of the hooded crow's proventriculus revealed some shared morphological features with most species of birds and some variations that might be attributed to their diet and feeding behaviour.

Ultrasonographic evaluation of the coelomic cavity in Rhode Island Red hybrid hens (Gallus gallus domesticus)

Backyard chickens are gaining popularity, and so is individual veterinary care for their health and management. Ultrasonography represents an important part of the imaging diagnostic arsenal in veterinary medicine; however, published data on its use in chickens are scarce and mostly focus on the reproductive tract. The objectives of this prospective, reference interval study were to describe a standard protocol for a full coelomic evaluation and the normal ultrasonographic appearance and measurements of the coelomic organs in awake and anesthetized healthy hens. The liver, gallbladder, gonad, gastrointestinal tract, pancreas, and spleen were clearly visualized in 21 Rhode Island Red hybrid hens (8 immatures, 13 adults) included in this study. In all animals, there was a scant amount of coelomic fluid, which was more visible at the cardiac apex. The cysticoenteric duct and hepatoenteric duct were visualized in 57% (12/21) of the hens. Seven hens were anesthetized and placed in dorsal decubitus, as the kidneys were not visualized in the hens while standing. Reference intervals were calculated for the splenic short and long axes, proventricular wall thickness, ventricular wall thickness, and duodenal wall thickness. Reference values were measured for the thickness of the pancreas, gallbladder wall, and kidneys, as well as the diameters of the biliary ducts. Moreover, five hens of different breeds were examined, and the results obtained were comparable to those of previous studies. The results of this study support the use of ultrasonography as a diagnostic tool in Rhode Island Red hybrid hens and provide reference ranges for use in hens with clinical diseases involving coelomic organs.

Early Nutrition with Different Diets Composition versus Fasting on Immunity-Related Gene Expression and Histomorphology of Digestive and Lymphoid Organs of Layer-Type Chicks

Simple Summary

With the continuous improvement in the progress of poultry industry, a better understanding of the avian immune system is necessary. A prolonged holding period (36–72 h), along with a delay in access to feed and/or water post-hatching, has a negative influence on performance, intestinal histomorphology, and the immune system development of chicks. Therefore, the present study aimed to investigate the effect of early feeding with different diet composition or delayed feeding during the first 72 h of chick’s life on the expression of immunity-related genes and histomorphology of digestive and lymphoid organs of layer-type chicks. Early nutrition post-hatching had no negative effect on the development of the lymphoid and digestive organs in chicks. Histomorphological examination revealed an increase in cortex and cortex:medulla of thymus and bursa in the early fed groups compared to the fasted ones, with resultant impacts on the primary lymphoid organs. Higher germinal center areas and white pulp of the spleen were recorded in the early fed chicks, implying augmented proliferation and maturation of B cells in the secondary lymphoid organs. In the liver, a strong positive reaction to Best’s carmine stain in the early fed groups, indicating that the liver of these chicks had numerous glycogen granules in the cytoplasm of hepatocytes. The expression levels of splenic-immunity related genes were up-regulated in most of the early fed chicks at 14 day of age. Our findings suggested that early feeding post-hatch can modify the splenic-immunity related genes and modulate the histomorphology of the digestive (liver and proventriculus) and lymphoid organ in layer-type chicks during the early life post-hatching.

Abstract

Early feeding post-hatching (EFPH) can impact the immune response and modify the immunity-related gene expression. Therefore, we aimed to examine the effects of EFPH with different diets composition versus fasting during the first 72 h of chick’s life on the histomorphological structures of the liver, proventriculus, central and peripheral lymphoid organs, and immunity-related genes in layer-type chicks during the brooding period. A total of 400 chicks were randomly allotted into 4 groups with 4 replicates each. The experimental groups during the first 72 h of life were: feed and water deprivation (control, T1), feeding a starter layer diet (20% CP and 11.84 MJ/kg ME, T2), feeding a starter layer diet contained 3% molasses in its composition (20% CP and 11.81 MJ/kg ME; T3), and feeding a starter broiler diet (23% CP and 12.68 MJ/kg ME, T4). After the first 72 h of chick’s life, all chicks were fed ad libitum the T2 diet. EFPH had no negative effect on the development of the lymphoid or digestive organs in chicks. Greater relative weights of the spleen and bursa of Fabricius (p < 0.05) were observed in the early fed chicks compared to control at day 14 of age. Histomorphological examination revealed an increase (p < 0.05) in thymus cortex and cortex:medulla in the T3 and T4 groups compared to the fasted ones at day 28 of age. Pelicae height, follicular width, cortex, and cortex:medulla of bursa were improved (p < 0.01) in the fed groups compared to fasted chicks, with resultant influences on the primary lymphoid organs. Compared to control, higher germinal center areas and white pulp of the spleen (p < 0.05) were recorded in the early fed chicks, implying augmented proliferation and maturation of B cells in the secondary lymphoid organs. In the liver, a strong positive reaction to Best’s carmine stain in the early fed groups, indicating that the liver of these chicks had numerous glycogen granules or greater glycogen density in the cytoplasm of hepatocytes. There was a significant enhancement in the proventriculus mucosal and gland thickness, as well as fold height (p < 0.05) in the early fed chicks. The expression levels of splenic Toll-like receptor 2, interleukin 4, tumor necrosis factor α, and interferon gamma were up-regulated (p < 0.01) in most of the early fed chicks (T2, T3, and T4) compared to fasted ones at 14 day of age. In conclusion, EFPH could modify the splenic-immunity related genes and modulate the histomorphology of the digestive (liver and proventriculus) and lymphoid organs in layer-type chicks during the brooding period.

Macro- and microstructures of the digestive tract in the Eurasian collared dove, Streptopelia decaocto (Frivaldszky 1838): Adaptive interplay between structure and dietary niche

We describe the functional morphology of the digestive tract of the Eurasian collared dove, Streptopelia decaocto using anatomical, morphometric, histological, histochemical, and ultrastructure techniques, and relate our findings to the species' dietary niche. Our results revealed that the esophagus is displaced on both sides of the neck and has highly folded tunica mucosa, which confer greater elasticity for efficient swallowing and passage of food to the crop. The proventriculus is delicate and its mucosal layer contains polymorphic glands with dense profound and superficial secretory units that open to the luminal surface by gastric pores. The ventriculus is biconvex and lined with a keratinized koilin membrane. The tubular glands within the mucosal lining include the isthmus, the neck, and the basal segment that comprise chief and basal cells with prominent nuclei. At the cuticle-mucosal interface, pyramidal vertical rodlets of the cuticle are secreted and superficially covered by a thin film of a horizontal matrix. The mucosa of the ileum form pyramidal villi that are oriented perpendicularly to the central lumen. Enterocytes infiltrated with goblet cells make up the epithelial lining of the villi. There are subtle differences in the thicknesses of corresponding tunics together with histochemical reactions of alcian blue (AB) and Masson-Goldner trichrome (MT) for their microstructures. Overall, our findings reveal remarkable convergence of both macro-and microstructures in S. decaocto to other granivorous species, and offer further evidence of the close association between functional morphology and feeding style relative to food swallowing, digestion, and absorption.